DEBBIE ELLIOTT, HOST:
Ash and smoke have blanketed the Caribbean island of St. Vincent for a week now. The volcano, La Soufriere, erupted on April 9 and shows no signs of slowing down. Thousands of people have been displaced from their homes. And the island is without basic services like water and electricity.
Richard Robertson remembers the last time the volcano blew in 1979. He's a geologist with the Seismic Research Centre at the University of the West Indies. Professor Robertson is also leading the center's response to the eruption. And we reached him at the Belmont Observatory in St. Vincent. Welcome.
RICHARD ROBERTSON: Thank you. Thank you. Good to be here.
ELLIOTT: So tell us what's happening now with the eruption. What is going on with the volcano right now?
ROBERTSON: Currently, the volcano is having episodes of explosive activity interspersed by episodes of heightened seismic activity. The seismic activity consists of discrete seismic events that we call long-period or hybrid earthquakes that are usually associated with magma moving. And therefore, the explosive activity that happens in between makes sense because when it explodes, it's because magma, which is rich in gas, has come to the surface. And it fragments the rock and produces explosions that, of late, have been of lower magnitude than the ones that we had earlier on.
ELLIOTT: So this sounds like a very dangerous situation. I understand the island has been ordered to evacuate. Water and electricity shortages are being reported. What are you hearing in terms of the humanitarian situation there? Has anyone been harmed?
ROBERTSON: No one has been harmed. This is an eruption in which we were able to detect the signals and the signs precursory to the explosive activity. So 24 hours before the volcano had its first explosion, the government took a decision to evacuate people. They did successfully. And no one have been killed.
ELLIOTT: So is there anything that makes this volcano different than others we hear about around the world, say, in Iceland or Hawaii, for example?
ROBERTSON: It's certainly different than the Icelandic and the Hawaiian volcanos. It's many times more dangerous. The Icelandic volcanoes tend to have a much more - what we call basaltic systems. So it has a much more runny lava. It moves, yes. It does a lot of damage when it moves. But it moves so slowly, it doesn't have that much explosive capacity. So you are able to observe it and stand near to it. You see pictures of people being very - practically on the volcano. Ours tend to have a different kind of magma. We produce material that is much more sticky, much more what we call viscous. The gas then gets trapped inside of it. And there's a greater potential for it to explode.
ELLIOTT: And I'm guessing there's no way of knowing what the extent of the damage is yet because it's not safe to go and look.
ROBERTSON: We use a lot of satellite imagery. So we have a good idea of the extent of the damage. We also use visual observations. We could see volcano all the time where we are. We use a Coast Guard boat. So we go around the coastal areas. And then from time to time, we use a helicopter. So we have a fair idea of where have been damaged and where have not so far.
ELLIOTT: Professor Richard Robertson is a geologist with the Seismic Research Centre at the University of the West Indies. He has been watching the volcano, La Soufriere, on St. Vincent. Thank you so much for giving us this update.
ROBERTSON: Thank you very much.
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